Bone turnover in passive smoking female rat: relationships to change in bone mineral density

Abstract

BackgroundMany studies have identified smoking as a risk factor for osteoporosis, but it is unclear whether passive smoking has an effect on bone mineral density and bone turnover and if such an effect could cause osteoporosis.The purpose of the study was to investigate the effect of passive smoking on bone mineral density (BMD) and bone turnover and the relationship between BMD and bone turnover in female rat.MethodsForty-eight female Wistar rats were randomized into six groups: 2-month, 3-month,4-month smoke-exposed rats and their controls. A rat model of passive cigarette smoking was prepared by breeding female rats in a cigarette-smoking box for 2, 3 or 4 months. Serums were analyzed for levels of osteocalcin, bone-specific alkaline phosphatase (b-ALP) and Tartrate-resistant acid phosphatase 5b (TRACP 5b). BMD was assessed at lumbar vertebrae and femur by dual energy X-ray absorptiometry in passive smoking rats and in control rats.ResultsBMD of lumbar spine and femur was lower in 4-month smoke-exposed female rats than that in controls. However, there was no significant difference in serum osteocalcin levels between smoke-exposed rats and controls. Significantly lower b-ALP and higher TRACP 5b were found in the 3-month or 4-month smoke-exposed rats compared to controls. Subsequent analysis showed that b-ALP positively correlated with BMD of the lumbar vertebrae(r = 0.764, P = 0.027) and femur(r = 0.899, P = 0.002) in 4-month smoke-exposed female rats. Furthermore, TRACP 5b levels negatively correlated with BMD of lumbar vertebrae (r = -0.871, P = 0.005) and femur (r = -0.715, P = 0.046) in 4-month smoke-exposed female rats.ConclusionOur data suggest that smoke exposure can inhibit bone formation and increase bone resorption. The hazardous effects of passive smoking on bone status are associated with increased bone turnover in female rat.

The Influence of Passive Tobacco Exposure and Physical Exercise on Bone Tissue of Young Rats

“…Similar to the findings of Gao et al 15 and Ino et al 16 , in this study we also observed that the groups exposed to cigarette smoke continued to show lesser measurements in comparison with the control group. …”

“…The study by Gao et al 15 found a statistically significant difference only after 4 months of exposure; the rats which were exposed for 2 or 3 months did not exhibit differences in the bone parameters studied 4 …”

The effect of hyperbaric oxygen therapy on fracture healing in nicotinized rats

“…Fung et al [28] reported that a 2-month period of nicotine application does not change BMC and BMD values. Gao et al [29] reported that 2-or 3-month periods of nicotine application did not change BMD values, but a 4-month period of application reduced BMD values. The controversial results were likely due to the variable dosages and methods of nicotine administration and the different healing models used to study the influence of nicotine.…”

‘Long‐term feeding effects of stevioside sweetener on some toxicological parameters of growing rats’

“…Some of the methods are outdated and some currently in use have been modified for automated testing, but all are old and do not reflect the best available techniques. In fact, given the importance of acid phosphatase to the conclusions of the paper, it is surprising that the authors did not use a current and commercially available rat‐specific immunoactivity assay for the TRAP isoform 5b that is specific for changes in bone metabolism, as was done in another recent paper (Gao et al ., ). Instead, an older colorimetric method for TRAP was used that is not specific for bone.…”

“…Reporting such information for critical analyses is not rare or unusual. Precision and accuracy data were recently reported for both bone‐specific ALP and bone‐specific TRAP assays by other authors investigating alterations in bone metabolism in the rat, even though they were using validated commercial kits for both tests (Gao et al ., ). Given the analytical problems observed in the hematology results reported by Awney et al .…”